MEMORANDUM **

Doug Wayne Smith appeals from his bench-trial conviction for escape from confinement, in violation of 18 U.S.C. § 751(a). We have jurisdiction pursuant to 28 U.S.C. § 1291, and we affirm.

Smith contends the district court erred by prohibiting him from collaterally attacking the validity of his prior conviction *614as a defense to the escape charge. We disagree.

A defendant may not use a challenge to the validity of a prior conviction as a defense to escape from confinement. See Lucas v. United States, 325 F.2d 867, 867 n. 2 (9th Cir. 1963); Bayless v. United States, 141 F.2d 578, 579-80 (9th Cir. 1944).

AFFIRMED.